for some reason, every time I race at Stromlo, I pick up scratches from blackberry bushes. I don't know where it is as I never actually feel it happen. It's usually on the 4th lap or so and I happen to casually look down and see that I have blood on my arm. When I clean it up it is the tiniest of scratches which is just exacerbated by the rush of blood through the pipes when racing hard.
Thanks to Trent and Sheree for sending this pic through via the berm website.